Alain Prost says that the arrival of Daniel Ricciardo at Renault will help to take the team to "another dimension."
Prost, who is a special advisor to the French manufacturer, believes that the former Red Bull Racing driver will bring useful knowledge to the team.
The Australian, who will partner Nico Hulkenberg, won seven races with Renault power over the past five seasons.
"We are very happy with the drivers we had in 2018, that's the first thing we must say," he told Autosport. "We're very pleased with Carlos [Sainz].
"But for sure Daniel will give, not another motivation because we don't need that, but he's going to be quite a big help to make the team even better.
"He's going to give us some information, he's going to make the team in another dimension."
Prost admits that Renault "missed some opportunities" in 2018 - but he's convinced that the team will make good progress this season, especially with its power unit.
He says that the team secured a solid fourth place in the World Championship despite turning its focus to future development.
"In fact if you look at all the teams you always have some ups and downs," he said.
"We were maybe not where we wanted to be in the summer, for different reasons, but we came back.
"The engine side was a little bit better, on the chassis side there were a few things where maybe we missed some opportunities.
"But we wanted to be fourth, or the best after the top three, and we wanted to be closer to them.
"It's very difficult to manage that, because we took a decision to prepare for next season in the best way, not to develop too much, especially around the engine.
"So in fact we've done exactly what we wanted to do so far. Now the next step is next season to be closer to the top teams."
Prost added that Renault's occasional setbacks were a natural part of its progress.
"You cannot be on an upwards line like this, there's always some steps," he said.
"Maybe we were a little bit disappointed by some races, for sure, but the good thing is that the team was able to get back to it. That's the answer I would say.
"It's really difficult to make one more step to where they [the leaders] are.
"One thing that is difficult to accept sometimes is that especially Ferrari and Mercedes made a big improvement with the engine. So we had to move, and we're really moving for this year."
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